It is known in the art to provide a pair of buoyant elongated hulls for use as water skis in towless water skiing, the user standing on these hulls and advancing on water as he would with cross-country skis, for example. Usually, orifices are formed intermediate the length of the elongated hulls on their upper surface, these orifices leading to their respective cavity, each of the latter being correctly dimensioned and adapted for inserting the user's feet. The user's feet are therefore positioned inside the hulls, the hulls upper surfaces being intermediate the user's feet and knees.
A search of the prior art has revealed several pertinent United States patents: U.S. Pat. No. 5,080,621, issued Jan. 14, 1992, to A. W. Nayes; U.S. Pat. No. 4,804,345, issued Feb. 14, 1989, to J. S. Lee; U.S. Pat. No. 3,027,576, issued Sep. 21, 1959, to S. R. Fines; U.S. Pat. No. 4,915,659, issued Apr. 10, 1990, to R. A. Sanders; and U.S. Pat. No. 4,129,912, issued Dec. 19, 1978, to W. L. Robinson.
The main problem that can be found in these (and other similar) inventions is their precarious stability. Indeed, a person standing on the hulls needs to keep his balance in spite of the skis tendancy to drift in a lateral outward direction. Also, the hulls may sway on one side or the other due to the high center of gravity of the user on the hulls, especially once the skis start drifting laterally away from the user.
To prevent the swaying movement, the user will have to exert a considerable ankle rigidness, to keep the hulls steady on the water surface. The outward drifting tendancy will also necessitate a considerable effort on the user's part to keep the skis in an acceptable position, i.e. parallel and separated by a constant distance approximately equal to the width of the shoulders. This effort will have to be combined to the anti-vacillating effort, and will therefore not only be extenuating for the user, but also it will require a great deal of coordination to keep his balance.
ROBINSON partially overcomes this problem by fixing several spring members between his hulls, thus preventing the hulls from drifting apart. But these spring members impede the translation movement of the nautical skier, for when one ski advances more than the other, the spring members exert a stress in both a perpendicular and a parallel direction, relative to the length of the skis. In other words, the spring members not only prevent the skis from drifting apart, they also hinder the back and forth movement that the user exerts on the skis. It is consequently more difficult for the user to travel the same distance with the ROBINSON skis than with skis that are not equipped with the springs.
Thus, it is the present inventor's belief that the existing inventions are not satisfactory in the field of the present invention, due to this lack of stability when the user stands on the hulls.